This invention relates to an improved plastic cover and to an improved method wherein molded hinge constructions as well as the provision of novel reinforcing ribs are facilitated during molding.
Refuse bin covers are often constructed by rotational molding utilizing cross-linked polyethylene. Such constructions often incorporate hinges which either require the insertion of metal tubes into the plastic hinge members or alternate upper and lower receiving openings for the metal hinge rods. While the metal tubes provide a positive and accurately aligned I.D., they are expensive requiring an additional manufacturing step. The alternate openings approach is less effective in that the hinges often spring out of engagement with the hinge rods. Since the hinge members are normally limited to the two thicknesses which forming upper and lower covers, breakage often occurs in these areas of maximum stress. Refuse bins constructed in accordance with U.S. Pat. No. 4,771,940 are representative of the prior art. While the patent contemplates limited nesting is provided to conserve space when stacking, the fact that respective upper and lower ribs of respective covers run in opposite directions precludes effective space conservation.